US6484522B2 - Screw compressor for refrigerating apparatus - Google Patents

Screw compressor for refrigerating apparatus Download PDF

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US6484522B2
US6484522B2 US09/884,016 US88401601A US6484522B2 US 6484522 B2 US6484522 B2 US 6484522B2 US 88401601 A US88401601 A US 88401601A US 6484522 B2 US6484522 B2 US 6484522B2
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motor
rotational speed
refrigerating apparatus
screw compressor
detector
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US09/884,016
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US20010054294A1 (en
Inventor
Noboru Tsuboi
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Kobe Steel Ltd
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Kobe Steel Ltd
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Assigned to KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.) reassignment KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.) ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TSUBOI, NOBORU
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/08—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by varying the rotational speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
    • F04C18/16—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2240/00—Components
    • F04C2240/40—Electric motor
    • F04C2240/403—Electric motor with inverter for speed control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/01—Load
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/18—Pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2270/00—Control; Monitoring or safety arrangements
    • F04C2270/19—Temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F25B1/04—Compression machines, plants or systems with non-reversible cycle with compressor of rotary type
    • F25B1/047—Compression machines, plants or systems with non-reversible cycle with compressor of rotary type of screw type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/02—Compressor control
    • F25B2600/021—Inverters therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/19—Pressures
    • F25B2700/193—Pressures of the compressor
    • F25B2700/1933—Suction pressures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2115—Temperatures of a compressor or the drive means therefor
    • F25B2700/21156—Temperatures of a compressor or the drive means therefor of the motor
    • F25B2700/21157—Temperatures of a compressor or the drive means therefor of the motor at the coil or rotor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F25B49/025—Motor control arrangements
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

  • the present invention relates to a screw compressor for refrigerating apparatus that is driven by a motor being controlled by an inverter.
  • a screw compressor for refrigerating apparatus adapted to control the rotational speed of each of motors for driving the compressor body and the liquid injection pump according to the increase and the decrease of load is known in Japanese Patent Laid-Open Publication No. Sho 57-18484.
  • This screw compressor has a suction pressure detector for detecting the suction pressure in its suction section, which pressure has a monotone increasing relationship with the cooling heat load, wherein a pressure signal outputted from the suction pressure detector is inputted to a variable voltage frequency converter via a pressure regulator, so that rotational speeds of a compressor body driving motor and a liquid injection pump driving motor are controlled simultaneously.
  • the above-mentioned screw compressor disclosed in Japanese Patent Laid-Open Publication No. Sho 57-18484 is controlled to increase the rotational speed of motor when the pressure detected by the suction pressure detector is higher than the predetermined value of pressure. Therefore, there is a problem in that the motor is apt to be overloaded, so that the endurance of the motor is deteriorated.
  • the screw compressor disclosed in Japanese Patent Laid-Open Publication No. Sho 59-211790 has a complicated construction because the slide valve is provided. Furthermore, the screw compressor is constructed so that the inverter is not used, i.e., a commercial power source is directly used without intervening the inverter, when the capacity of this screw compressor is in the range of 100 to 75% by the slide valve, whereby there is a problem in that the inverter is not sufficiently used.
  • the present invention provides a screw compressor for refrigerating apparatus comprising: a screw rotor; a motor for driving said screw rotor, the rotational speed of said motor being controlled through an inverter; a heat load detecting means for detecting a cooling heat load; a load condition detecting means for detecting the heat load condition of said motor; and a motor rotational speed controlling device for controlling the rotational speed of said motor based on a heat load signal from said heat load detecting means and a load condition signal from said load condition detecting means.
  • said motor rotational speed controlling device can be configured to control the rotational speed of said motor to be reduced if the compressor capacity is determined as excessive based on said heat load signal or if the load condition of said motor is determined as excessive based on said load condition signal, and to control the rotational speed of said motor to be increased if the compressor capacity is determined as lacking based on said heat load signal and the load condition of said motor is determined as not excessive based on said load condition signal.
  • a detector for detecting the suction pressure of said screw compressor or a detector for detecting the temperature of cooled liquid, emanated from an evaporator in said refrigerating apparatus can be used.
  • a detector for detecting the coil temperature of said motor a detector for detecting the electric current that is supplied to said motor, a detector for detecting the temperature of refrigerant gas that is discharged from said screw compressor, a detector for detecting the rotational speed of said motor and the like can be used.
  • FIG. 1 schematically shows a refrigerating apparatus incorporating a screw compressor according to the present invention
  • FIG. 2 shows a relationship between the suction pressure and the cooling heat load of the screw compressor in the refrigerating apparatus shown in FIG. 1;
  • FIG. 3 is a flow chart illustrating the control of the screw compressor in the refrigerating apparatus shown in FIG. 1;
  • FIG. 4 schematically shows a refrigerating apparatus incorporating another screw compressor according to the present invention
  • FIG. 5 schematically shows a refrigerating apparatus incorporating still another screw compressor according to the present invention
  • FIG. 6 is a flow chart illustrating the control of the screw compressor in the refrigerating apparatus shown in FIG. 5;
  • FIG. 7 schematically shows a refrigerating apparatus incorporating yet another screw compressor according to the present invention.
  • FIG. 8 is a flow chart illustrating the control of the screw compressor in the refrigerating apparatus shown in FIG. 7;
  • FIG. 9 schematically shows a refrigerating apparatus incorporating yet another screw compressor according to the present invention.
  • FIG. 10 is a flow chart illustrating the control of the screw compressor in the refrigerating apparatus shown in FIG. 9;
  • FIG. 11 schematically shows a refrigerating apparatus incorporating yet another screw compressor according to the present invention
  • FIG. 12 is a flow chart illustrating the control of the screw compressor in the refrigerating apparatus shown in FIG. 11;
  • FIG. 13 schematically shows a refrigerating apparatus incorporating yet another screw compressor according to the present invention
  • FIG. 14 is a flow chart illustrating the control of the screw compressor in the refrigerating apparatus shown in FIG. 13;
  • FIG. 15 schematically shows a refrigerating apparatus incorporating yet another screw compressor according to the present invention.
  • FIG. 16 is a flow chart illustrating the control of the screw compressor in the refrigerating apparatus shown in FIG. 15 .
  • FIG. 1 illustrates a refrigerating apparatus 10 A incorporating a screw compressor 1 A according to the present invention, in which a circulation flow path 14 is formed for flowing the refrigerant through the screw compressor 1 A, a condenser 11 , an expansion valve 12 and an evaporator 13 .
  • the screw compressor 1 A comprises a pair of engaging male and female screw rotors 21 , a motor 22 for rotating the screw rotors 21 , a discharging portion 23 and a motor coil temperature detector D 1 , wherein the motor 22 is adapted to be operated by a power supplied from a power source supplying line 24 via an inverter 25 .
  • the condenser 11 is provided with a cooling water inlet Ci and a cooling water outlet Co and the evaporator 13 is provided with a cooled liquid inlet Bi and a cooled liquid outlet Bo.
  • an superheat degree detector D 2 for detecting the superheat degree of refrigerant gas emanated from the evaporator 13 is provided, so that the opening extent of the expansion valve 12 is controlled according to the detected superheat degree.
  • a suction pressure detector D 3 for detecting the suction pressure of the screw compressor 1 A is provided, so that a pressure signal indicating the detected pressure is inputted from this suction pressure detector D 3 into a controller 26 and simultaneously, a temperature signal indicating the detected temperature is inputted from a motor coil temperature detector D 1 into the controller 26 .
  • the suction pressure is a factor indicating the cooling heat load of the refrigerating apparatus 10 A and the motor coil temperature is a factor indicating the load condition of the motor 22 . And based on both of these signals, frequency conversion of power is performed in the inverter 25 and the motor 22 is controlled as explained later.
  • the suction pressure of the screw compressor 1 A and the cooling heat load of the refrigerating apparatus 10 A have a relationship of wherein and the cooling heat load increases as the suction pressure increases.
  • the suction pressure is too low, the cooling heat load is so small that the capacity of the screw compressor 1 A becomes excessive, and thus it is necessary to reduce the consumption power by reducing the rotational speed of the motor 22 to reduce the capacity of the screw compressor 1 A.
  • the suction pressure is too high, it is needed to increase the capacity of the screw compressor 1 A by increasing the rotational speed of the motor 22 , because the capacity of the screw compressor 1 A becomes lacking due to the increased cooling heat load.
  • the suction pressure belongs to Z region, it is needed to increase the capacity of the screw compressor 1 A by increasing the rotational speed of the motor 22 , but if the rotational speed of the motor 1 A is excessively increased, the motor 22 becomes to an overload condition and the overload condition should be avoided.
  • the process passes to a step for determining whether the motor coil temperature is below the predetermined upper limit value (YES) or not (NO) and this determination is made in the controller 26 . If YES, the process passes to a step for increasing the rotational speed of the motor 22 and a signal increasing frequency of power for the inverter 25 is outputted from the controller 26 , so that the rotational speed of the motor 22 will be increased.
  • the process passes to a step for reducing the rotational speed of the motor 22 and a signal for reducing the frequency of power outputted from the controller 26 to the inverter 25 , thus the rotational speed of the motor 22 is decreased even if the suction pressure is in Z region, because the motor 22 is considered as being in the overload condition.
  • all of the cases are returned to the first step and each of the above-mentioned steps is repeated.
  • the capacity of the screw compressor 1 A is regulated in response to the change of cooling heat load, without causing the overload of the motor 22 .
  • FIG. 4 shows a refrigerating apparatus 10 B using another screw compressor 1 B according to the present invention, in which drawing the constituents of the refrigerating apparatus common to those of the refrigerating apparatus 10 A shown in FIG. 1 are indicated with same reference numerals and descriptions thereof will be omitted.
  • a cooled liquid temperature detector D 4 is provided in the flow path for cooled liquid emanated from the evaporator 13 , instead of the suction pressure detector D 3 shown in FIG. 1, so that a temperature signal indicating the detected temperature is inputted from the cooled liquid temperature detector D 4 into the controller 26 .
  • the refrigerating apparatus 10 B shown in FIG. 4 is substantially identical to the refrigerating apparatus 10 A shown in FIG. 1, so that it is possible to make determination as to where a suction pressure belongs among the X, Y and Z regions based on the temperature signal from the cooled liquid temperature detector D 4 , and the flow chart shown in FIG. 3 can be correspondingly applied to the refrigerating apparatus 10 B shown in FIG. 4 .
  • FIG. 5 shows a refrigerating apparatus 10 C incorporating still another screw compressor 1 C according to the present invention, in which drawing the constituents common to those of the refrigerating apparatus 10 A shown in FIG. 1 are indicated with same reference numerals and descriptions thereof will be omitted.
  • the refrigerating apparatus 10 C is provided with a current detector D 5 for detecting the magnitude of motor current of the power supplied to the motor 22 instead of the motor coil temperature detector D 1 shown in FIG. 1, so that a current signal indicating the detected current is inputted from the current detector D 5 into the controller 26 .
  • a control is performed in which a step for determining whether the motor current is below the predetermined upper limit value (YES) or not (NO) is included instead of the step for determining whether the motor coil temperature is below the predetermined upper limit value or not as shown in FIG. 3 .
  • YES the predetermined upper limit value
  • NO the step for determining whether the motor coil temperature is below the predetermined upper limit value or not as shown in FIG. 3 .
  • This control is substantially identical to that shown in FIG. 3, except that the overload condition of the motor 22 is determined based on the motor current.
  • FIG. 7 shows a refrigerating apparatus 10 D incorporating still another screw compressor 1 D according to the present invention, in which drawing the constituents of the screw compressor 10 A common to those of the refrigerating apparatus shown in FIG. 1 are indicated with same reference numerals and descriptions thereof will be omitted.
  • the refrigerating apparatus 10 D is provided with a discharge temperature detector D 6 for detecting the temperature of refrigerant gas compressed and discharged from the screw rotors 21 in the discharging portion 23 instead of the motor coil temperature detector D 1 shown in FIG. 1, so that a temperature signal indicating the detected temperature is inputted from the discharge temperature detector D 6 into the controller 26 .
  • a control is performed in which a step for determining whether the discharge temperature of the compressed refrigerant gas from the screw rotors 21 is below the predetermined upper limit value (YES), or not (NO) is included instead of the step for determining whether the motor coil temperature is below the upper limit value or not as shown in FIG. 3 .
  • YES the predetermined upper limit value
  • NO the discharge temperature
  • This control is substantially identical to that shown in FIG. 3, except that the overload condition of the motor 22 is determined based on the discharge temperature.
  • FIG. 9 shows a refrigerating apparatus 10 E incorporating still another screw compressor 1 E according to the present invention, in which drawing the constituents of the screw compressor 10 E common to those of the refrigerating apparatus 10 A shown in FIG. 1 are indicated with same reference numerals and descriptions thereof will be omitted.
  • the refrigerating apparatus 10 E is provided with a motor rotational speed detector D 7 for detecting the rotational speed of the motor 22 instead of the motor coil temperature detector D 1 shown in FIG. 1, so that a rotational speed signal indicating the detected rotational speed is inputted from the motor rotational speed detector D 7 into the controller 26 .
  • a control is performed in which a step for determining whether the rotational speed of the motor is below the predetermined upper limit value (YES) or not (NO) is included instead of the step for determining whether the motor coil temperature is below the predetermined upper limit value or not as shown in FIG. 3 .
  • YES the predetermined upper limit value
  • NO the step for determining whether the motor coil temperature is below the predetermined upper limit value or not as shown in FIG. 3 .
  • This control is substantially identical to that shown in FIG. 3, except that the overload condition of the motor 22 is determined based on said rotational speed of the motor.
  • a frequency detector D 7 for detecting the frequency may be provided on the inverter 25 or its secondary side instead of the motor rotational speed detector D 7 , so that a frequency signal indicating the magnitude of detected frequency is inputted from the frequency detector D 7 into the controller 26 .
  • a step for determining whether the frequency is below the predetermined upper limit value or not is included instead of the step for determining the magnitude of rotational speed of the motor in FIG. 10 .
  • Each of the refrigerating apparatus described in the above is provided with only one type of detectors among the motor coil temperature detector D 1 , the cooled liquid temperature detector D 4 , the current detector D 5 and the like in order to determine the load condition of the motor 22 .
  • the present invention is not limited to a certain type of detectors, and covers refrigerating apparatus provided with two or more detectors suitably selected from these detectors. Selected detectors may include all or some of the detectors described in the above to determine the load condition of the motor 22 and the combination thereof is optional.
  • FIG. 11 shows a refrigerating apparatus 10 F to which a screw compressor 1 F provided with the motor coil temperature detector D 1 and the discharge temperature detector D 6 , in which drawing the constituents common to those of the refrigerating apparatus explained in the above are indicated with same reference numerals and descriptions thereof will be omitted.
  • the determination as to where a suction pressure belongs among X, Y and Z regions is made; if it is determined that it belongs to Z region, two steps for determining signals from two detectors are interposed before arriving at the step for increasing the rotational speed of the motor. Namely, if it is determined that the suction pressure belongs to Z region, the process passes to the step for determining whether the motor coil temperature is below the predetermined upper limit value (YES) or not (NO). If NO, the process passes to the step for reducing the rotational speed of the motor because the motor is considered as in the overload condition.
  • YES predetermined upper limit value
  • NO the process passes to the step for reducing the rotational speed of the motor because the motor is considered as in the overload condition.
  • the process passes to the step for determining whether the discharge temperature is below the upper limit value (YES) or not (NO), because it can not be considered that the motor 22 is in the overload condition merely based on the motor coil temperature. If NO, the process passes to the step for reducing the rotational speed of the motor because the motor 22 is considered as in the overload condition, and if YES, the process passes to the step for increasing the rotational speed of the motor because the motor 22 is considered as not in the overload condition.
  • the control flow thereafter is identical to those described in the above.
  • the determination as to whether the motor 22 is in the overload condition or not is doubly made based on two factors.
  • FIG. 13 shows a refrigerating apparatus 10 G incorporating a screw compressor 1 G additionally provided with the current detector D 5 in addition to the motor coil temperature detector D 1 and the discharge temperature detector D 6 , in which drawing the constituents common to those of the refrigerating apparatus explained in the above are indicated with same reference numerals and descriptions thereof will be omitted.
  • this refrigerating apparatus 10 G a step for determining whether the motor current is below the upper limit value (YES) or not (NO) is added to the control flow chart thereof in addition to the flow chart shown in FIG. 13 .
  • the determination as to whether the motor 22 is in the overload condition or not is trebly made based on three factors.
  • the order of three determination steps as to the motor coil temperature detector D 1 , the discharge temperature detector D 6 and the current detector D 5 is optional rather than limited thereto.
  • FIG. 15 shows a refrigerating apparatus 10 H incorporating a screw compressor 1 H additionally provided with the motor rotational speed detector D 7 in addition to the motor coil temperature detector D 1 , the discharge temperature detector D 6 , and the current detector D 5 , in which drawing the constituents common to those of the refrigerating apparatus explained in the above are indicated with same reference numerals and descriptions thereof will be omitted.
  • a step for determining whether the rotational speed of the motor is below the upper limit value (YES) or not (NO) is added in the control flow chart in addition to the flow chart shown in FIG. 14 .
  • the order of four determination steps as to the motor coil temperature detector D 1 , the discharge temperature detector D 6 , the current detector D 5 and the motor rotational speed detector D 7 is optional rather than limited thereto.
  • the cooled liquid temperature detector D 4 may be provided instead the suction pressure detector D 3 .
  • the suction temperature is introduced based on the temperature signal from the cooled liquid temperature detector D 4 and then the determination as to where the suction pressure belongs among X, Y and Z regions is made in the control flow.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
US09/884,016 2000-06-23 2001-06-20 Screw compressor for refrigerating apparatus Expired - Lifetime US6484522B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2000-189537 2000-06-23
JP2000189537 2000-06-23

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US6484522B2 true US6484522B2 (en) 2002-11-26

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EP (1) EP1172563B1 (de)
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US20080307810A1 (en) * 2007-06-15 2008-12-18 American Standard International Inc Operational limit to avoid liquid refrigerant carryover
US8622725B2 (en) 2010-11-26 2014-01-07 Kobe Steel, Ltd. Mechanical compression ratio changing screw compressor

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US7412842B2 (en) 2004-04-27 2008-08-19 Emerson Climate Technologies, Inc. Compressor diagnostic and protection system
US7275377B2 (en) 2004-08-11 2007-10-02 Lawrence Kates Method and apparatus for monitoring refrigerant-cycle systems
KR20070053939A (ko) * 2005-11-22 2007-05-28 삼성전자주식회사 냉장고 및 그 제어방법
US8590325B2 (en) 2006-07-19 2013-11-26 Emerson Climate Technologies, Inc. Protection and diagnostic module for a refrigeration system
JP4949768B2 (ja) * 2006-08-10 2012-06-13 日立アプライアンス株式会社 スクリュー圧縮機
US20080216494A1 (en) 2006-09-07 2008-09-11 Pham Hung M Compressor data module
US20090037142A1 (en) 2007-07-30 2009-02-05 Lawrence Kates Portable method and apparatus for monitoring refrigerant-cycle systems
US8393169B2 (en) 2007-09-19 2013-03-12 Emerson Climate Technologies, Inc. Refrigeration monitoring system and method
US9285802B2 (en) 2011-02-28 2016-03-15 Emerson Electric Co. Residential solutions HVAC monitoring and diagnosis
US9759469B2 (en) * 2011-08-31 2017-09-12 Johnson Controls Technology Company System and method for controlling a variable speed drive of a compressor motor
US9480177B2 (en) 2012-07-27 2016-10-25 Emerson Climate Technologies, Inc. Compressor protection module
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EP1172563A2 (de) 2002-01-16
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EP1172563A3 (de) 2003-01-02
EP1172563B1 (de) 2008-01-23

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